1. Field of the Invention
The present invention relates to the stabilization of highly unsaturated fatty acids and derivatives thereof. These unsaturated compounds have at least three (3) to six (6) double bonds and would include all the cis forms of 5, 8, 11, 14, 17- eicosapentaenoic acid (EPA), which contains five of such double bonds, and all the cis forms of 4, 7, 10, 13, 16, 19-docosahexaenoic acid (DHA), which contains six of such double bonds, and all the food grade derivatives thereof. The CAS Registry No. of EPA is 10417-94-4 and that of DHA is 6217-54-5. The stabilization is accomplished by the use of certain water activated enzyme containing systems as disclosed hereinafter. The unsaturated compounds are preferably microencapsulated in a wall member containing the enzyme.
2. Description of the Prior Art
EPA and DHA are derived in the form of neutral triglycerides, glycolipids, phospholipids, etc., from marine fats, algae and fungi, and are used in the form of various food grade derivatives thereof, in foods and as a medicament for preventing or ameliorating thrombo-embolic conditions. Because of their highly unsaturated structures, these compounds are very prone to oxidation, and when oxidized may have a highly unpleasant and rancid odor. Upon ingestion, they also cause a phenomenon known, physiologically, as "fish oil belch," which is also an undesirable trait of various of these compounds.
Although various attempts have been made by those in the art to place various of these compounds in a condition or system that would stabilize them against oxidation and render the compounds more organoleptically acceptable during and after ingestion, none have been entirely successful in providing a means to accomplish both ends successfully.
U.S. Pat. Nos. 4,211,865, 4,497,710 and 4,615,839 disclose the preparation of EPA and/or DHA and/or some derivatives thereof.
U.S. Pat. No. 4,526,902, UK Nos. 1,604,554 and 2,033,745 disclose the use of EPA and/or DHA and/or certain derivatives thereof in the treatment or prophylaxis of thrombo-embolic conditions.
U.S. Pat. No. 4,525,306, UK Nos. 1,604,554 and UK 2,033,745 disclose the encapsulation of EPA and/or DHA in capsules of gelatin.
U.S. Pat. No. 4,438,106 discloses the encasing of EPA and DHA and certain derivatives thereof in cyclodextrin.
U.S. Pat. Nos. 4,021,364; 4,225,581; 4,269,821; 4,322,311; 4,324,683; 4,329,332; 4,525,306; UK No. 2,166,651; PCT W086/03676 and PCT WO 86/06252 disclose the encapsulation of various types of biologically active materials or pharmaceuticals in various types of polymeric materials. PCT W086/03676 discloses the use of gelatin as one of such polymeric materials in the coacervation coating process of such publication.
U.S. Pat. Nos. 4,525,306, 4,554,107; 4,623,488; UK Nos. 1,604,554 and 2,033,745 disclose the use of certain antioxidants with EPA and/or DHA, or fish oils containing EPA.
U.S. Pat. Nos. 4,554,107 and 4,623,488 disclose that fish oil containing EPA may be deodorized in a multistep molecular interesterification and distillation process to remove malodorous fractions therefrom.
In a Ph. D. University of Rhode Island dissertation by Yi-Hua Lin, published in 1987, by UNI Dissertation Information Service, 300 N. Zeib Road, Ann Harbor, Michigan 48106, entitled "Inhibition of Lipid Oxidation In Fatty Fish by Glucose Oxidase Preservation", the use of a glucose oxidase/catalase/glucose enzyme system alone, and with an invertase/glucose oxidase/catalase/sucrose system was used to inhibit lipid oxidation in fresh mackeral.
The dissertation also investigated the effects of catalase, glucose oxidase and hemoglobin on lipid oxidation in a model system.
U.S. Pat. No. 3,962,425 discloses that lipophytic enzymes may be used to accelerate the putrefaction of fish.
U.S. Pat. Nos. 4,405,649 and 4,419,370 disclose the use of proteolytic enzymes to treat fish so as to retard curd formation or to liquify the fish.
U.S. Pat. Nos. 3,920,521, 3,997,402 and 4,029,819 disclose the use of superoxide dismutases as antioxidants in foodstuffs containing, inter alia, lipids.
EPA 172,432 discloses the simultaneous use of ascorbic acid oxidase and encapsulated organic acid as a catalyst for use with nitrite picked meats so as to lessen the amounts of nitrites needed to produce red coloration in the meat.
EPA 207,039 discloses the use of certain oxidases and a substrate therefor in combination with catalase and superoxide dismutase to prevent oxidation in beverages and other foods having a pH lower than 5.